However, since the eel has a much larger potential difference, the effects can be severe.

Electrochemical potential difference drives the reaction.

British Dictionary definitions for potential difference

potential difference

noun

1.

the difference in electric potential between two points in an electric field; the work that has to be done in transferring unit positive charge from one point to the other, measured in volts U, ΔV, Δφ, pd Compare electromotive force